BALB/c mice injected with irradiated myeloma cells of a myeloma tumor (MOPC-167) of BALB/c origin form 1) antibodies that are specific for a surface antigen on cells of other BALB/c myeloma tumors, and 2) cytotoxic T lymphocytes (CTLs) that are a) specific for MOPC-167 and b) crossreact with many lymphomas of another mouse strain (DBA/2). Attempts will be made to identify the antigens recognized by the antibodies and CTLs. The specific CTLs to vesicular stomatitis virus-infected cells will also be studied as models to aid in developing general procedures for identifying the antigens recognized by CTLs. In a second line of investigation, the rare lambda 2 light chains of mouse immunoglobulins will continue to be studies as probes to the mechanism by which immunologic diversity originates. Several BALB/c myeloma tumors that produce lambda 2 chains have been identified and amino acids sequences of these chains will be compared with lambda 2 315, the prototype lambda 2 chain.